Antibodies to carbohydrate antigens

Abstract

The present invention discloses novel monoclonal antibodies and functional fragments thereof that specifically bind to SLeA carbohydrate antigen with high specificity and selectivity. The invention further provides compositions comprising the antibodies or fragments thereof as well as uses of the antibodies, fragments and compositions.

The invention claimed is: 
     
         1 . A monoclonal antibody (mAb) or a fragment thereof that specifically binds to Sialyl Lewis A glycan (SLeA), wherein the mAb or the fragment comprises an antigen binding domain comprising a heavy-chain variable domain (VH) and a light-chain variable domain (VL) each comprising three complementarity determining regions (CDRs), wherein the VH-CDR 1, 2 and 3 comprise amino acid sequences SEQ ID NOs: 15, 12, and 8, respectively, and the VL-CDRs 1, 2 and 3 comprise amino acid sequences SEQ ID NO: 9, 10, and 11, respectively. 
     
     
         2 . The mAb or fragment according to  claim 1 , wherein VH-CDR1 comprises amino acid sequence selected from SEQ ID NO: 6 and 15, and the VH-CDR2 comprises amino acid sequence selected from SEQ ID NO: 12 and 21. 
     
     
         3 . The mAb or fragment according to  claim 1 , wherein the CDRs 1, 2, and 3 of the VH domain comprises amino acid sequences SEQ ID NOs: 15, 21 and 8, respectively, the CDRs 1, 2, and 3 of the VL domain comprise amino acid sequences SEQ ID NOs: 9, 10 and 11, respectively, VH-framework domains (FRs) 1, 2 and 4 comprising amino acid sequences SEQ ID NOs: 24, 26 and 27, respectively, and a VL-FR1 comprising the amino acid sequence SEQ ID NO: 28. 
     
     
         4 . The mAb or fragment according to  claim 1 , comprising:
 i. a set of six CDR sequences comprising SEQ ID NOs: 15, 21, 8, 9, 10 and 11;   ii. a set of four VH framework sequences comprising SEQ ID NOs: 24, 26, 29 and 27;
 and 
   iii. a set of four VL framework sequences comprising SEQ ID NOs: 28, 30, 31 and 32.   
     
     
         5 . The mAb or the fragment according  claim 1 , wherein the VH domain comprises amino acid sequence set forth in SEQ ID NO: 3 and the VL domain comprises amino acid sequence set forth in SEQ ID NO: 5. 
     
     
         6 . The mAb or the fragment according to  claim 1 , wherein the fragment is a single chain variable fragment (scFv). 
     
     
         7 . The mAb or the fragment according to  claim 6 , wherein the scFv comprises amino acid sequences SEQ ID NO: 3 and SEQ ID NO: 5. 
     
     
         8 . The mAb or the fragment according to  claim 7 , wherein the scFv comprises amino acid sequence SEQ ID NO: 22 or an analog thereof having at least 90% sequence identity to said sequence. 
     
     
         9 . The mAb or the fragment according to  claim 1 , characterized by at least one of:
 (i) the mAb or the fragment binds SLeA glycan with an equilibrium dissociation constant (K D ) of from about 0.1 to about 30 nM;   (ii) the selectivity of said mAb or the fragment to SLeA glycan is at least 90%;   (iii) the mAb or the fragment is a chimeric antibody or fragment:   (iv) the mAb or the fragment has an IgG structure; and   (v) the light chain constant region is selected from kappa and lambda.   
     
     
         10 . A conjugate comprising the mAb or the fragment according to  claim 1 . 
     
     
         11 . A pharmaceutical composition comprising the mAb or the fragment according to  claim 1  or a conjugate thereof, and a pharmaceutically acceptable carrier. 
     
     
         12 . A kit for diagnosing a cancer in a subject, wherein the kit comprises the mAb or the fragment according to  claim 1  or a conjugate thereof and means for detecting the amount of the mAb or the fragment bound to cells of the biological sample. 
     
     
         13 . A monoclonal antibody (mAb) or a fragment thereof that specifically binds to Sialyl Lewis A glycan (SLeA), wherein the mAb or the fragment comprises an antigen binding domain comprising a heavy-chain variable domain (VH) and a light-chain variable domain (VL) each comprising three complementarity determining regions (CDRs) and four framework (FR) domains, wherein the VH-CDR 1, 2 and 3 comprise amino acid sequences SEQ ID NOs: 15, 12, and 8, respectively, the VL-CDRs 1, 2 and 3 comprise amino acid sequences SEQ ID NOs: 9, 10 and 11, respectively, the VH-FRs 1, 2 and 4 comprises acid sequences SEQ ID NOs: 23, 26 and 27, respectively, and the VL-FR 1 comprises acid sequence SEQ ID NO: 28. 
     
     
         14 . The mAb or fragment according to  claim 13 , wherein the CDRs 1, 2, and 3 of the VH domain comprises amino acid sequences SEQ ID NOs: 15, 21 and 8, respectively, the CDRs 1, 2, and 3 of the VL domain comprise amino acid sequences SEQ ID NOs: 9, 10 and 11, respectively, the VH-(FRs) 1, 2 and 4 comprise amino acid sequences SEQ ID NOs: 24, 26 and 27, respectively, and the VL-FR1 comprising the amino acid sequence SEQ ID NO: 28. 
     
     
         15 . The mAb or the fragment according to  claim 13 , wherein the fragment is a single chain variable fragment (scFv). 
     
     
         16 . A conjugate comprising the mAb or the fragment according to  claim 13 . 
     
     
         17 . A kit for diagnosing, cancer in a subject, wherein the kit comprises the mAb or fragment thereof according to  claim 15  or a conjugate thereof and means for detecting the amount of the antibodies or antibody fragments bound to cells of the biological sample.